Test temperature gauge out of car

Got a 74 Charger with Rally dash. Clock and temperature gauge don't work, along with a few lights. My ordering me a quartz conversion for clock for Christmas (she likes look of clock) so I'll be taking the dash apart. Can you check if a gauge is bad when it's out of the car? Not big on electrical so looking for help here.

I suspect it may be in gauge since I tried grounding sending unit and gauge didn't move. Also found a few places where sending unit wire has been repaired so it has been damaged/shorted(?) before. Any help would be appreciated.

So you grounded the sending unit wire to a good ground? To check gauge while its out first ohm across it with a meter set to ohms if you get a value it's most likely good if no value the gauge is toast. If the first test is good you can check the accuracy with three different value resistors. Connect one stud on the gauge to 12v ground and series in one resistor at a time from the other stud to 12v positive. 73.7 ohm resistor will be the low temp Mark 23 ohm resistor is half way on gauge and 10.2 is full temp. These resistor values can be rounded off to the nearest whole number.

Awesome Beekeeper, thanks! I'll be giving it a try here shortly.